<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>登录页</title>
    <style>
        .opt {
            background-image: linear-gradient(to right, skyblue, pink);
        }
        @media screen and (max-width: 768px) {
            .login {
                background-color: red;
            }
        }
    </style>
</head>
<body>
    <div class="login">
        <h3>账号登录</h3>
         <div class="opt">
             <input type="text" placeholder="请输入账号">
         </div>
    </div>
</body>
</html>